An increased content of very long chain fatty acids (VLCFA), namely of lignoceric and cerotic acids, was confirmed in a number of fibrolast cell lines derived from patients with adrenoleukodystrophy (ALD). ALD cells oxidized labeled palmitate, lignocerate, or cerotate at a lower rate than normal cells, but the reduction in the metabolism of VLCFA was only moderately larger (by 40-60%) than the reduction in palmitate oxidation. The oxidation of VLCFA was shown to depend on carnitine, which demonstrates mitochondrial involvement in this process.